How is energy yield uncertainty quantified for renewable energy projects?

Energy yield uncertainty combines multiple sources using Monte Carlo simulation or analytical propagation. Sources include: resource measurement (instrument accuracy, data coverage), long-term adjustment (correlation uncertainty, reference period representativeness), spatial variation (extrapolation from measurement to turbine/array), wake/shading models, power curve/performance ratio, availability, curtailment, and degradation. Each source has probability distribution. Combined uncertainty expressed as P-values: P50 (median, 50% probability of exceeding), P75 (75% confidence for debt sizing), P90 (90% confidence for conservative case). Bankable yields often use P50 with uncertainty adjustments.